"These assets are devolved to the financing of the Syrian regime," the Swiss court said in a statement.

Noting the "highest probability that Makhlouf is close to the Syrian government and that there is a risk of financial support to the Syrian government," the court added: "It is necessary to prevent sanctions imposed by Switzerland's trading partners being circumvented on Swiss territory."

According to the Swissinfo news agency, Assad has relied on businessmen close to him, most notably Makhlouf, to help keep Syria's economy afloat.

Makhlouf is subject to international sanctions but uses intermediaries to do business.